Highschool dxdxd
by Raximus
Summary: My oc everybody's favorite ultimate dark night 'replaces' Issei is the plot and tries to find smth interesting. Too powerful oc and harem naturaly.
1. Chapter 1

**DICLAIMER: I own nothing except my oc.**

**High school DxDxD**

**Ch. 1 an odd way to end a first date**

Kuoh Academy yard It was a beautiful sunny day at Kuoh Academy there we found D, the ultimate dark knight, who has enrolled in the school as a second year under the name Issei Hyoudou, and the reason for that is cause he wanted to experience school life. He is enjoying the time between classes his sides are Matsuda and Motohama two notorious perverts and because D was bored, he often accompanied them at their peeping and other 'activities' which gave him the stigma of pervert as well and making them the 'Perverted Trio'.

"Ah, this so damn annoying." Matsuda practically screamed in despair as he stood up.

"What is?" D asked curiously as he too stood up.

"It's our second year in Kuoh Academy a previously all-girl school and none of us had any let alone a girlfriend." Matsuda lamented in despair.

"And to think there are so many free girls with hot curvy bodies in the academy especially those transfer students from overseas. " Motohama added in despair as he stood up as well.

"Who knows girls aren't as simple as we are." D commented.

As they were announcing their thoughts about they heard a group of three giggling the three turned and they saw them approaching a blond haired 'pretty boy'.

"Hey Kiba what are you doing right now?" One happily asked. "Yeah, you maybe want to sing karaoke with us?" Another happily added.

"Thanks, but I have a meeting with my club." He answered politely while his face seemed to sparkle. "Ah, that's too bad." One of them said. "I really wish I could go though, thank you ladies for inviting me." He said to them and then left.

"Kiba Yuuto, class 2-C basically every girl wants him…" Motohama stated in annoyance. "…And every guy wants him dead." Matsuda added in anger.

"Forget about Kiba, the Kendo club is going to start changing in a little while and you don't want to miss it, do you?" D said in a playful tone.

"Oh, yeah those breasts and those legs." Matsuda monologued while he started losing himself in his own little world.

"Hey, are you coming Issei?" Motohama asked.

"Nah, I'm not in the mood today, I will wait you in the 'safe' place we agreed. Have fun." D replied.

…

**The 'safe' place**

"Oh, look at you guys judging by your state you got caught right?" D commented in an almost cheery tone as he saw his perverted friends arriving at a bruised beat up state.

"Hey give me a break, just cause they never managed to corner you when they caught you peeping you shouldn't be treating it as it is nothing." Matsuda complained in a weird voice due to his bruised face.

D or Issei had been caught many times peeping as well but every time he was chased he either had easily outrun his pursuers or climbed the fence and escaped them.

"Now that you mentioned it, with your physical abilities you could have easily become the ace at one of the sports clubs, but you haven't even tried to join them, why?" Motohama asked.

"Not, interested I'd rather hang with…" D started to say sensed someone watching him.

As he turned and looked up at the window of a school building D saw a beautiful girl with flowing crimson red hair and blue-green eyes looking at them, and then waking away from the window.

"Rias Gremory her measurements are B98-W58-H90 cm she is the president of the occult, club transfer student from abroad." Motohama informed with an informative perverted tone in his voice.

"Just look at those things!" Matsuda added in a dreamy voice. "99 not 98, and she has beautiful not just amazing breasts." D corrected with a naughty smile on his face.

…

**Occult club room**

"Who was that boy?" Rias asked Akeno Himejima a girl with long black hair in a ponytail, white skin and violet eyes.

"Which one?"

"The one with the spiky black hair."

"Well he is in the class 2-B, if I remember correctly his name is Issei Hyoudou. Why do you ask?"

"An, nothing I just wondered who he is that's all."

…

**On top of a bridge during sunset**

D-Issei was yawning and lamenting the current situation.

"I enrolled in a school with quite a few probably demonic presences and nothing 'supernaturally' interesting has happened, if it wasn't for those two I would have already left."

Suddenly D felt someone non-human coming to his direction. It was a pretty girl with long black hair.

"Excuse me, you are Issei Hyoudou from Kuoh academy correct?" She asked D politely.

"Yeah, that's me."

"I just wanted to ask you a quick question…" She paused while her face had started to become red "…Are you… are you seeing anyone." She asked with a voice filled with shyness.

"No, and to make this easier for you if you are asking me out the answer is yes, I would love to go out with you." D said and gave the girl a smile.

"Ah, really… ah…my name is Yuuma Amano so…are you free this Sunday afternoon?"

"Yes I am."

The two exchange phone numbers and set a place and an hour for the date and then they parted.

'Things are finally starting to move.' D thought while he pretended not to notice the tiny girl, with the white hair who was wearing Kuoh academy uniform and kitty hairpieces, who thought that was following him in secret.

…..

**Sunday date's meeting place**

D was wearing a light black jacket with a red shirt underneath and black pants and was waiting patiently for his date.

"Here take a flyer." A girl wearing a red dress with bat-like wings for decoration on the shoulders and the back said to him while giving him a flyer.

'Couldn't this bat have used a less obvious transformation?' D thought while the girl-bat was leaving. 'And what's this all your wish will be granted.'

D wasn't an expert on magic and circles but he was certain that the magical circle on that flyer was a summoning circle.

"Issei hey."

D turned his head and saw Yuuma. Walking towards him.

"Oh, hey Yuuma."

"Did you wait long?"

"No, I'm just glad you came."

D-Issei and Yuuma started their date by checking out a bunch of different store, in which D bought a cheap but pretty bracelet and then to a café.

After the café they went to a park for a stroll.

When they reached a fountain Yuuma said "Can I ask you a question? In honor of our first date there is something I would like you to do." She said while going closer and closer to D.

"Sure, you can ask me for whatever you want."

"Would you die for me?" Yuuma said in a changed voice with an ominous look at her face.

"What?" D said in a confused tone.

"I want you to die for me." She said to his ear.

"Gua ha ha ha." She started laughing while black wings sprout from her back and her clothes disappeared into and an evil revealing leather outfit appeared in their stead.

"AAAAH, just please tell me why before you kill me." D said in a scared tone.

"Hmm, you could just blame god for giving you the sacred gear." She replied while a lance of purple light was formed into her hands.

Yuuma then proceeded to stab D-Issei in the stomach but D effortlessly avoid it and with a quick movement he pummeled a dumfounded Yuuma to the ground with one punch.

"I will give you a 20/100 for a good performance in your assassination attempt, but seriously you didn't stand a chance against me."

"Now to get back at you." D said with a fiendish smirk to his face.

…..

**A few minutes later **

D was walking away from the fountain.

"Sigh." "I wish I knew what was all that about."

"Wait a minute." He then took the flyer with the summoning circle and focused his mana on it to forcefully activate it (instead of using the strength of his desire).

The flyer shined and it turned into a big magical circle from which a beautiful girl with crimson red hair and huge boobs appeared.

"Why am I not surprised?" D commented Rias arrival in an amused tone.

"Huh, you are okay?" Rias asked in confusion.

"Yeah, sorry to disappoint you miss Gremory."

"If that is your real name miss demon." He added in a more serious tone.

"How do you know?"

"You appeared out of a magical circle…

…And you are just too beautiful." Rias blushed on the compliment.

"Now I have a ton of questions for you, and I'm guessing you want to go to the occult research club to talk since it is your headquarters, right?"

"Yes, you are quite informed." Rias said as she regained her composure.

"More deductions than anything else." D said as they made their way to Kuoh Academy.

…..

**Kuoh Academy occult research club room**

The club room interior was a wood-paneled room with Victorian-style coaches and chairs along the walls.

Inside there were waiting a handsome young man with short blonde hair and grey eyes who D recognize as Kiba Yuuto, a third year with long black hair and violet eyes and Koneko Toujou a petite first year girl.

"This is Akeno Himejima vice-president of the club, Kiba Yuuto and Koneko Toujou."" Rias to introduce everyone.

"Hello, my name is Issei Hyoudo nice to meet you everyone." D said with a smile.

"Would like some tea?" Akeno asked.

"No, thanks."

"Now to business." D said in a serious tone. "Who was the girl with the black wings, what is a sacred gear and what is it that you want from me, cause otherwise you wouldn't give me this." D showed the flyer.

"This will be a long explanation and maybe difficult to believe but everything I will say to you is true."

…..

**At the park near the fountain**

At a part of the grass where the ground oddly seemed recently dug, the dirt began to stare.

Suddenly a hand clad in black leather came out and then a head belonging to 'Yuuma Amano'.

"I swear… I will kill… that bastard … even if it's… the last… thing… I will ever… do!" 'Yuuma' said in a raucous voice filled with hatred.

**And cut.**

**Author's note: this is it folks my first crossover with my oc character who I already establish as a Disgaea character i may make more with him as the main character and I promise I will explain more about his powers in the next ch. And I'm gonna an unexpected guinea pig for it. Leave a review if have smth nice to say.**


	2. Chapter 2

**DICLAIMER: I own nothing except my oc.**

**Ch. 2 dragon emperor vs dark knight**

Last time Issei Hyoudo a.k.a. D the ultimate dark knight after he buried alive a would be assassin with black wings he summoned Rias Gremory a devil and president of the occult research club for answers.

"The person who tried to kill you was a fallen angel." Rias said in a serious tone.

"Fallen angels, once servants of god who fell from grace due to impure thoughts and desires." Rias explained.

"They along with angels and us devils fought in a great three-sided war long ago, the war ended with a ceasefire due to the enormous loses."

"Hmm, I got it. Please continue." D said.

"They tried to kill you because of the sacred gear you have in your body. A power unintentionally given to some special humans. "

"Wait, what do I have in me?" D said in surprise.

"A sacred gear a weapon of great power, some of them can destroy devils or angels with little effort if they are mastered." Akeno added.

"Makes sense that they wanted me dead, but what about you, am I not a threat to you?" D asked while trying to put some fear into his voice.

Rias smiled and said in an extravagant voice.

"Hyoudo Issei I would like to offer you to become a member of the illustrious Gremory clan, by becoming a devil you will gain power and you will live for 10,000 years."

D not impressed at all by the offer said.

"And how exactly are you gonna turn me into a devil?"

Then out of nowhere a chessboard appeared on Rias hands. On it there were a knight, a bishop, arook and eight pawns.

"With these." Rias said.

"Because of the war the number of devils decreased drastically and because it is devils have long lifespan it is difficult for us to have children so we created the evil piece system to increase our numbers." Rias explained.

"Before I make any life changing decisions how do I use a sacred gear?" D asked.

"Simply, raise your left hand close your eyes and imagine the strongest image you can muster."

"Let me try." D said while raising his hand.

'Focus, focus.' D thought and then looked at Rias lower half (at her panties) 'Mm, classy and see-through very good. '

'What, the hell am I thinking I need to focus.'

"Ouch!" D said in surprise as he felt his left hand being electrified.

"Oh my, are you okay." Akeno said with a weirdly happy tone.

"What happened?" Rias asked.

" 'Rejection' should have guessed this would happened."

"Rejection? What do you mean by that?"Rias asked.

"Well you see, even though I have been born in this world, I have spent most of my life in a different universe." D confessed with a nervous smile.

A deadly silence fell then.

"Liar." Koneno said in a kinda whispered voice.

"Well it is a bit unbelievable Issei-san." Kiba agreed.

D then sigh and took the keys of his house out of his pocket space (the place where disgaea characters put their stuff.).

"Is the average human capable of that? Moreover how else do you explain that I survived unscathed from my encounter with that fallen angel."

"Listen my mother was from this world then she ended up in my fathers' world, they fell in love and when my mother found a way home she preferred to stay with my father and visit grandpa and grandma who lived in this city."

"During one of those visits my mother gave birth to me that must be why I have a sacred gear inside me."

"The reason why I can't take it out is because in my father's world they use a different system to manipulate mana, so I unless I can change my body to use your system I can't use it." D concluded.

Everybody then looked at D with a sense of wonder in their eyes.

"So, what you are saying is that you have to turn into a devil in order to access your sacred gear." Rias said.

"Ah, whatever let's give it a shot." D said in defeat.

"Are you sure you should make such a decision just like that." Rias said with a smile and a drop of sweat in the back of her head.

"Yes, just please use the knight on me I think it suits me."

Rias then took the knight and tried to use it on him with no luck.

"It seems that a knight is not enough." Rias said.

D sigh. "Then what do we do?"

"If a knight is not enough the rook and the bishop won't be either so we will have to try with six or more pawns." Rias explained.

"Not my first choice but let's give it a shot." D answered.

Rias tried with 6 pawns and then with 7 finally with 8 the reincarnation was complete.

Issei felt his body change as he changed from a human to a devil then black wings appeared from his body and a red light covered his left hand that took the form of a red clawed gauntlet.

Issei then had a 'vision' of a red western dragon.

"What the…" Issei tried to say before he returned to reality.

"The boosted gear one of the thirteen Longinus!" Rias said in amazement while everybody else was too shocked to speak.

"What is a Longinus and why did I just had a vision with a red dragon?" Issei said in confusion?

"Longinus are the thirteen top-tier Sacred Gears with enough power to kill Gods." Akeno explained having overcome her surprise.

"And yours is the boosted gear that has one of the two heavenly dragons sealed in it with the ability to double your magical power every ten seconds." Rias added.

"Wow that is an impressive ability."

Then a voice coming from the jewel of the gauntlet said. "_Thank you but the impressive one here is you, none of my previous hosts had summoned the boosted gear in his first time normally they would summon Twice Critical-like Sacred Gear at first." _

"And you are?" Issei said to his left arm.

"_My name is Ddraig the Welsh Dragon the sekiryutei although now we share the title nice to meet you partner._"

"Nice to meet you too Ddraig."

"This has must been quite the day for I suggest you return home and get some rest, we will talk about your duties tomorrow" Rias said.

"I will do that, goodnight everyone." Issei said happily before he left.

After Issei left. "Well, what do you think about him?" Rias asked the rest of her servants.

"He seems interesting." Akeno said in a cheery tone.

"Weird." Koneko said.

"What about you Kiba?" Rias asked Kiba.

"The way he walk say that he is an experienced warrior, though I would like to know more about him." Kiba said seriously.

"Yes, he is a mystery but it will be better not to force him to tell us more about him." Rias said knowing that everyone had a painful past.

….

**Hyoudou residence**

Since he had come to this world Issei had been living in his grandparents home who had passed away years ago.

After he had taken a bath and finished eating his meal he went to his room and sat to the floor and took a meditation stand.

"Now let's see what this new power is all about."

Issei then went into a deep meditation state.

…..

**Inside D's mind**

Issei opened his eyes and saw a barren rocky landscape. The 'sun' was setting and there was a red color across the skies. In front of him stood a large western red dragon.

"Well, aren't you full of surprises, what is this place?" Ddraig

"My inner world a place that reflects my thoughts, and this place is modeled after the battlefield of my greatest battle."

"You wanted to show me this for what reason?"

"This the place of our duel. You see I have a feeling that if I defeat you I will be able to take over you power and I don't like the idea of using your power without earning it for myself. "

'Plus I don't the idea of having a dragon in my body that is not under my control.' D thought.

Ddraig then started laughing.

"Ha h ha ha ha, and do you realy think you stand a chance again… groan. " Ddraig had begun saying until a giant black fist had connected with his face moving him a little from his position.

The one responsible was D, the giant black was connected to his right hand and was corresponding to his hand's movement.

Ddraig then saw D and noticed that his eyes were also entirely black.

"You asked for it." Ddraig said in mild anger before breathing fire on D.

The fire surrounded D but was then blown away by an air wave.

D then appeared from the flames smiling and wielding his sword (a big katana like the one Auron from final fantasy x is using).

"You will need to hit me with something better than weak flames."

D then moved with inhuman speed and slashed Ddraig's leg.

Ddraig then groaned and flew to the sky.

"Let's see how you will fight a dragon on his natural environment, the endless sky."

D smirked and a pair of wings made from the same dark substance as the giant arm appeared on his back.

"Like this." He said as flew to the sky.

_**BOOST, BOOST, BOOST, BOOST.**_

And then Ddraig unleashed a red beam from his mouth.

"Mugetsu." D simply said as he swung his sword and unleashed a large wave of pitch black energy.

The two attacks connected and canceled each other out which resulted in a large explosion.

And like this the battle continued for several hours.

Both the human and the dragon were tired and only slightly hurt.

"Ha ha ha, you are quite strong, not many could have fight me as an equal I'm impressed." Ddraig said.

"You are not bad yourself."

"But surely you should have realized that this fight could go on forever without a winner so let's stop this pointless battle."

"Hmm, you are right this has go on for quite a bit, so I will end it with my full power." As D finished saying that darkness surrounded him and took the form of an armour. (the design of the armour is that of Ventus from kingdom hearts but it has a black coloring and it doesn't have the horn-like ornament on the helmet).

"What the…." Ddraig said as he felt the atmosphere had become heavier.

Then D disappeared from his sight.

D then reappeared on top of his head and the edge of his sword lightly touched Ddraig's head.

"Immpossible!" Ddraig only manage to whisper as he got cut into large pieces that fell on the earth.

D then dispelled his armour and landed near Ddraig's head.

"Tell me why didn't you use that armour from the beginning."

"My skills would get dulled if I always used overwhelming power against my oppoments."

"I see, so what happens now?"

"Let's see what will happen if I try to take your power and use it through the devil pieces." D said as he placed his hands on Ddraig.

Then a light engulfed from and from that light Issei stepped out wearing a red dragon themed armour(yes he just achieved balance breaker just like that).

"Interesting what exactly is this?"

"Scale mail the balance breaker of the boosted gear, balance breaker is the evolved form of Sacred Gears. None of the previous wielders achieved balance breaker that fast, though none of them challenged me and defeated me." Ddraig said with a hint of shame.

"Really, I just can't wait to see what see what this baby can do in the real world." Issei said with a wicked glee.

"About that, I would appreciate if you don't use balance breaker for a while it seems our battle and the way you gained balance breaker put quite a strain on my soul."

"No problem, I doubt I would have to fight anyone powerful enough to force me to use it, at least for a while."

"Goodbye then, I think I will go and rest for now." Ddraig said as the armour vanished.

After Ddraig left from D's shadow a dark form started to take shap.

When it formed completely the being was black with the exception of his red glowing eyes (like a heartless neo-shadow from kingdom hearts) it had muscular frame and long horizontal horns.

"You got a new friend should I be jealous?" The being said even though it seemed it had no mouth.

"What do you want?" D said annoyed.

"I'm bored and I can't reach you unless you come here."

"So you want to talk?"

"What I want you is to take the final step so I can be released from this state of … I don't know what it is."

"The final 'step' as you called it would make life more boring for me and give me nothing in return except that I won't have to meet you again."

"So you are just going to play servant to that red haired girl hiding your power from her, do you really like boobs that much?" The being said in aggravation.

"It's not just her breasts but the rest of her group seems to have their respective dark past, I felt it and so did you. Let's just say I find them interesting and this time I might be able to fight with them seriously without doing all the work for them."

"Ha, we both know that trouble will come and when it does you will fight as D and not as Hyoudo Issei." And then the being returned to the shadows from whence it came.

**Please review and no flames on the reviews.**


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